How bring Modded Cars Online (Save Wizard?)

What do I look for when trading nodded cars?

3D paint ? What’s that?
White wheels? If so do you mean white wheels on rims that aren’t lowrider rims?

How do I know the vehicles I traded a plane and jet pack for were in fact modded, ?

They have Yankton plates yes,
By the paint jobs are just like a liklme green, is this paint not attainable in LSC ,?

I’m new to this but I would to get into the trading cars, and build up a collection of modded vehicles and rares .

I would appreciate any advice or help here.